Changes between Version 212 and Version 213 of UvmatHelp


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Timestamp:
Dec 15, 2022, 7:12:00 PM (2 years ago)
Author:
sommeria
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  • UvmatHelp

    v212 v213  
    609609To calibrate at once a set of experiments, a better alternative is the command '''[REPLICATE]'''. Open a folder  '''Campaign''', parent of the folders '''Experiment''' to treat. The GUI '''data_browser.fig''', also described in [#a3.7Dataorganisationinaproject section 3.7], then pops up. A two-column display appears, with the list of '''Experiments''' on the left and the list of corresponding '''[!DataSeries]''' on the right. Select the list of experiments to calibrate, and a single camera name in '''[!DataSeries]''', then validate by pressing '''[OK]'''.
    610610
    611 -''' 3D calibration''': 3D projection is handled by the options in '''[calib_type]''' '3D_lin' or '3D_quad' (if non-linear distortion is significant). By default, the set of calibration points is assumed to be contained in a single plane ''z''=0. For a correct determination of the 3D features, the normal to this plane must be tilted with respect to the line of view. Otherwise this problem of indetermination can be resolved by using a set of (typically 5-10) calibrations images using a plane grid with different tilting angles (for precision the grid must cover a large area of the view field). On each image, get calibration points with the tool '''[!Tools/Detect grid]''', introducing the appropriate grid mesh. Do not fill info on ''z'' coordinates. Store the points each time (without applying calibration at this stage), which fills the list [!ListCoordFiles] of file names. Then introduce a last grid image which will be considered as defining the orientation of the ''z'' axis, perpendicular to the grid. Detect points on this last image, but instead of storing them, apply the calibration with the option 3D_linear or 3D_quadr. A non-zero ''z'' position of this grid can be introduced by a z translation performed with '''[!Tools/Translate points]'''.
     611-''' 3D calibration''': 3D projection is handled by the options in '''[calib_type]''' '3D_lin' or '3D_quad' (if non-linear distortion is significant). By default, the set of calibration points is assumed to be contained in a single plane ''z''=0. For a correct determination of the 3D features, the normal to this plane must be tilted with respect to the line of view. Otherwise this problem of indetermination can be resolved by using a set of (typically 5-10) calibrations images using a plane grid with different tilting angles (for precision the grid must cover a large area of the view field). On each image, get calibration points with the tool '''[!Tools/Detect grid]''', introducing the appropriate grid mesh. Do not fill info on ''z'' coordinates. Store the points each time (without applying calibration at this stage), which fills the list [!ListCoordFiles] of file names. Then introduce a last grid image which will be considered as defining the orientation of the ''z'' axis, perpendicular to the grid. Detect points on this last image, but instead of storing them, apply the calibration with the option 3D_linear or 3D_quadr. A non-zero ''z'' position of this grid can be introduced by a z translation performed with '''[!Tools/Translate points]'''. It is generally convenient to do all these calibrations in air. Then transposition to water is done by the tool 'set_slice', see section 8.3.
    612612
    613613-''' Intrinsic parameters''': the previous procedure first determines the extrinsic parameters which characterize the camera optics (focal lengths and nonlinear deformation parameter). Then the extrinsic parameters, translation and rotation of the camera with respect to the reference grid, are determined on the last grid image. If the same optics is used in a new experiment, it is possible to skip the multiplane detection, importing the intrinsic parameters from a previous <!ImaDoc> file by the menu bar tool '''[Import.../Intrinsic parameters]''', then applying the calibration with the option '3D_extrinsic' with the reference grid image only.
    … …  
    656656
    657657 * <!PointCoord>: [x y z X Y] , where x,y,z are the physical coordinates of each point, X Y its image coordinates.
    658  
    659  The parameters defining the slice positions are in the XML element <!ImaDoc/Slice> as follows:
    660 
    661  * <!NbSlice>: nbre of slices 
     658
     659The parameters defining the slice positions are in the XML element <!ImaDoc/Slice > as follows:
     660
     661 * <!NbSlice>: nbre of slices
    662662
    663663 * <!CheckVolumeScan>=0 for the multilevel case (position is given by index i modulo !NbSlice ), =1 for volume scan (position is given by index j)
    … …  
    665665 * <!SliceCoord>: [x y z] positions (!NbSlice lines) of the !NbSlice planes. For volume scan with translation, x=y=0, z= slice height. For angular scan, [x,y,z]=[coordinate on the rotation axis].
    666666
    667  * <!SliceAngle> set of !NbSlice angles. !SliceAngle(i,1) = angle of rotation around x axis for  plane #i . !SliceAngle(i,2) = angle of rotation around y axis for plane #i. ( !SliceAngle(i,3)=0 is not used)
     667 * <!SliceAngle> set of !NbSlice angles. !SliceAngle(i,1) = angle of rotation around x axis for  plane #i . !SliceAngle(i,2) = angle of rotation around y axis for plane #i. ( !SliceAngle(i,3)=0 is not used)
     668 * <! InterfaceCoord> =[0 0 h] where h is the z coordinate of the upper surface ( top view assumed)
     669 * [wiki:RefractionIndex <RefractionIndex]> index of refraction of the fluid (=1.33 by default), to use if clibration was done in air.
    668670
    669671== 9 - Masks and grids ==
    … …  
    838840The button '''[TEST]''' allows the user to witness the correlation as a live plot. It first opens the source image in a new figure '''view_field'''. By moving the mouse in the figure, the local correlation box and the corresponding search box are drawn in the image, and the 2D correlation result then appears in a new figure 'Figure1 Image Correlation' which automatically pops up. It is possible to freeze the current correlation plot, and get the values in the Matlab work space, by left mouse selection. The figure belows shows the correlation process and the '''[!SearchBox]''' and '''[!CorrBox]''' explained before.
    839841
    840   [[Image(civ1_test.jpg)]]    [[Image(Correlation for PIV.png)]]
     842  [[Image(civ1_test.jpg)]]     [[Image(Correlation for PIV.png)]]
    841843
    842844The grid determines the positions of measured velocity vectors: it sets the central positions of the correlation boxes (in pixels) for the first image. A default regular grid can be set by the meshes '''[num_Dx] ''' and '''[num_Dy]''' (in pixels). Alternatively a custom [#a9.2Grids grid] can be stored in a text file and selected by the check box '''get grid'''. This is convenient to limitate the processing to a subregion or to fine tune the resolution.
    … …  
    10271029----
    10281030== 13 - Editing XML files with the GUI editxml ==
    1029   This GUI '''   editxml.fig'''    visualises and edits XML files. It is automatically called by the browser of '''   uvmat.fig'''    when a file with extension .xml is opened.
     1031  This GUI '''    editxml.fig'''     visualises and edits XML files. It is automatically called by the browser of '''    uvmat.fig'''     when a file with extension .xml is opened.
    10301032
    10311033When an input file is opened, editxml detects the title key, e.g. <!ImaDoc>, and looks for the corresponding XML schema (e.g. {!ImaDoc.xsd} ). This schema is sought  in the directory defined by <!SchemaPath> in the installation file {PARAM.xml} of UVMAT. If the schema is found, the hierarchical structure and keys given by the schema are diplayed.  Otherwise the  keys of the XML file are displayed.